Association between urinary crystals and bacterial flora in urinary tract infection suspected patients

Abstract

Urinary stones are an increasing clinical problem in Sri Lanka. It has been reported that 1/10 individuals experience urinary stones, yet the mechanisms responsible remain unknown. Bacteria have long been recognized to contribute to urinary crystals. However, the role of bacteria in development of urinary crystals has not been extensively investigated. This study was carried out to investigate the association between urinary bacteria flora and urinary crystals in patients with symptoms of urinary tract infections (UTI). Forty five UTI suspected patients were enrolled in the study. Mid-stream urine specimens were collected and cultured on Hi-Chrome UTI culture media. Culture plates were incubated at 37 ºC for 18-24 hours. Colony appearance and colony count were recorded and this was followed by urinary crystal count by crystal concentration technique. The Fisher’s exact test was carried out to determine the association between urine crystals and presence of urinary bacterial flora. Out of 45 subjects, 29 were positive for urinary crystals, where 14 were females and 15 were males. Nineteen patients were culture positive while 18 were positive for both crystals and culture. The patients between 30-40 years showed a higher possibility to have urinary crystals and organisms. Predominant crystal type and organism detected were calcium oxalate and coliforms, respectively. Male patients in 30-40 years presented with a higher crystal concentration compared to other males. All female patients, between 30-40 years, who were positive for coliforms and presented with higher crystal concentration compared to other females in the study population. A significant association (p <0.001) was observed between presence of urinary crystals and bacterial flora in UTI suspected patients.